1. Field of the Invention
The present invention relates to whey protein-containing granules and a method for producing the same.
2. Background Art
The whey protein is a protein contained in the milk serum (whey) obtained by removing casein and the like from milk, and comprises lactoalbumin, lactoglobulin, lactoferrin, and the like as main components. A whey protein is known to have such functions as a stamina improver, a fatigue reliever, an immunity enhancer, and the like, and in addition it is used as a protein supplement material in an athletic nutrient food, a diet food, and the like. The powders of this whey protein are highly hygroscopic, and when attempt is made to be dissolved in water as they are, the surface of powder clumps becomes a sort of candy to form lumps. Once they form lumps, the complete dissolution becomes difficult unless the lumps are broken with care and patience.
In order to make a hardly-soluble raw material soluble, making granules by binding the powders by granulation thereby facilitating penetration of water into them is generally practiced, and several attempts have been made to make whey protein-containing granules. For instance, the Japanese Patent Laid-Open Publication No. S63-22172 discloses a powdered or a granulated food composition composed of whey powders and the like and a surface active agent for foods in a liquid or a paste form. In this composition, a viscid surface active agent for foods is mixed with whey powders in order to improve handling properties of it, and the invention is nothing to do with the solubility of whey itself, thus the content of the surface active agent is high. Also, the Japanese Patent Laid-Open Publication Nos. H10-84868 and 2003-189799 discloses a milk substitute composition mainly containing whey and the like, characterized by containing lecithin and a polyoxyethylene glycerin fatty acid ester in it. This intends to suppress segregation of fat in the milk substitute and contains 10% by weight or more of fat, and thus does not have to do with dissolution of whey powders. In addition, as far as the present inventors know, when the compositions disclosed in these prior arts were dissolved in water, in any of these cases turbidity was observed, not resulting in transparency.